I have a '93 4Runner 3.0 auto, as per many previous threads...it's a PIG! I've swiss cheesed the airbox w/K&N. I'm considering getting a cat back exhaust. Several other performance cars I've owned have not had cats at all. Here in WV, we do not emissions test. Now.........I realize it's environmentally irresponsible, but would eliminating the cat all together(in addition to a cat back exhaust) help the 3.0 run better or increase fuel mileage?

 

not only is removing the cat environmentally irresponsible (did you know that all else being equal that cars with out a cat pollute about 100 times more than cars with a cat?), it's a federal offence. so i'd stay away from it.

but to answer your question, you won't get much in the way of gains from that. the 3.0 is slow and to make an appreciable amount of horsepower takes serous dollars. i wouldn't risk it by taking off the cat.

 

risk what??

 

I did.

 

lol...... I did on my 84 well because I have a 302 in it but i might be putting two on

 

you'll get mild gains...the chances of getting in trouble, as enviromentally illresponsible as it is, are practically zero....I mean come on, who is gonna check to see if you have a cat since you dont have emission testing? A US Marshall?

 

Not this again...

 

You won't get much if anything for additional power, you may even lose power. What you will get is a noisier exhaust system, and the guilt of this
hanging over your head. Posts like this make us look bad as a whole. Please be responsible and leave it in there. You can always replace it with a "high flow" convertor.

 

Not "us", me!

The stock exhaust has 160K on it. I'm wondering if the OEM cat could be somewhat clogged.

 

You are part of the membership, it's an "us" issue if discussed here. Removing the CAT is illegal. We don't promote it.

You may or may not get any gains, it will smell bad, gas mileage will get worse, and it will mess with the environment.

Why don't you make a sensible choice and regear to regain some power.

 

Just replace it with a high-flow cat, if you want to replace it at all. They really aren't that expensive. Get a Carsound one. For all intents and purposes, you'll never make significantly more power with the 3.0 without major modifications.

 

Thanks for the advice! It will stay put when I bolt on the rear section.

 

Glad to hear it On these cars, it just doesn't make enough difference to warrant the pollution.

 

I completly hollwed my cat and I am no more of a pollutant than a new explorer, I passed my emmissions. I was 2.5 times below the legal limit with a 125000mi 3.0. I suggest you eliminate. It cruises down the highway.

 

Some people just don't get it.

 

 

 

lol ok so i think we get the point cutting your cat off is foolish, but how about a highflow cat? anyone have one?

 

cebby, maybe a noob question but why would the gas mileage get worse without any cat in place? something with the back pressure?

 

Bingo. The 3.0 needs some BP to generate it's torque. Notice the complaints of those who have gone to large diameter exhaust? No torque!!